PubMed Health⌕ Search

Biomedical subjects

Yukiko Tsuji

Publications and source records attributed to Yukiko Tsuji.

10 recordsLinked to original sources
PubMed2005

Unexpected behavior of coniferin in lignin biosynthesis of Ginkgo biloba L.

To gain insight into the behavior of monolignol glucoside in Ginkgo biloba L., we examined glucosides potentially involved in lignin biosynthetic pathway. Coniferin (coniferyl alcohol 4O-beta-D-glucoside) is a strong candidate for the storage form of monolignol. Coniferaldehyde glucoside may also have a role in lignin biosynthesis; this was examined with tracer experiments using labeled glucosides fed to stem segments. A series of tracer experiments showed that coniferin and coniferaldehyde glucoside were modified into coniferyl alcohol and then efficiently incorporated into lignin under the experimental conditions used. Interestingly, more than half of the administered coniferin underwent an oxidation to the aldehyde form before its aglycone; coniferyl alcohol was polymerized into lignin. This suggests that there is an alternative pathway for coniferin to enter the monolignol biosynthetic pathway, in addition to the direct pathway beginning with the deglucosylation of coniferin catalyzed by beta-glucosidase. Enzymatic assays revealed that coniferaldehyde glucoside was produced enzymatically from coniferin, and that coniferaldehyde glucoside can be deglucosylated to yield coniferaldehyde, which could be fated to become coniferyl alcohol . Albeit the findings cannot be taken as proof for the in-planta functioning, these results present a possibility for the existence of alternative pathway in which some of the stored coniferin is oxidized to coniferaldehyde glucoside, which is deglucosylated to generate coniferaldehyde that joins the monolignol biosynthesis pathway.

Cinnamates↗
PubMed2004

Behavior of monolignol glucosides in angiosperms.

To examine the behavior of cinnamaldehyde and cinnamyl alcohol glucosides in lignifying tissues, angiosperms were subjected to tracer experiments using radioisotope-labeled and stable isotope-labeled glucosides. The aglycone from coniferaldehyde glucoside was efficiently incorporated into guaiacyl and syringyl lignin as a cinnamyl alcohol unit. The aglycone from coniferin was also incorporated into guaiacyl and syringyl lignin. However, some of the coniferin-derived aglycone that was incorporated into lignin passed through a cinnamaldehyde form prior to dehydrogenative polymerization. When coniferin was administered together with coniferaldehyde glucoside, syringyl units were rarely synthesized from coniferin via the cinnamyl alcohol stage, whereas numerous syringyl units were synthesized from coniferaldehyde glucoside. These observations suggest that the coniferaldehyde form is crucial for the biosynthesis of syringyl lignin in angiosperms.

Acrolein↗
PubMed2004

The behavior of deuterium-labeled monolignol and monolignol glucosides in lignin biosynthesis in angiosperms.

To examine the behavior of monolignol and monolignol glucosides in lignin biosynthesis, pentadeutero[9-D(2), 3-OCD(3)]coniferyl alcohol and pentadeutero[9-D(2), 3-OCD(3)]coniferin were synthesized and fed to growing Eucalyptus camaldulensis and Magnolia kobus. The differences in the incorporation patterns of these labeled precursors were studied using gas chromatography-mass spectrometry (GC-MS). Both precursors were incorporated into lignin, but the labeled coniferyl alcohol was incorporated more directly, resulting in a high proportion of pentadeutero-labeled guaiacyl and syringyl units in newly formed xylem, while labeled coniferin tended to be incorporated in lignin as tetradeutero units, especially in syringyl lignin in both trees. However, the incorporation efficiencies of the precursors into syringyl lignin were higher in Magnolia than in Eucalyptus, and the ratios of tetradeutero to pentadeutero in guaiacyl lignin were lower in Magnolia than in Eucalyptus when the trees were fed coniferin.

Cinnamates↗
PubMed2003

Changing pattern of deiminated proteins in developing human epidermis.

Peptidylarginine deiminases are widely distributed, calcium-ion-dependent enzymes that convert arginine residues of proteins into citrulline residues. This reaction, deimination, is thought to be an important event during the final stage of epidermal differentiation, possibly associated with integration and disintegration of keratin filaments. To elucidate the possible roles of protein deimination during human epidermal development we investigated localization of deiminated proteins using anti-citrulline peptide antibody, which preferentially recognizes citrulline residues in the V subdomains of keratin 1, and anti-chemically modified citrulline antibody, which enables detection of citrulline residues independent of amino acid sequences. Anti-chemically modified citrulline antibody, but not anti-citrulline peptide antibody stained the periderm in two-layered epidermis of 49 d and 57 d estimated gestational age. In the stratified epidermis of 88 d, 96 d, and 108 d estimated gestational age fetal skin, anti-citrulline peptide antibody and anti-chemically modified citrulline antibody staining was seen in the periderm and intermediate cell layers. After periderm cells regressed and keratinization began in the interfollicular epidermis, anti-citrulline peptide antibody and anti-chemically modified citrulline antibody were restricted to the cornified cell layers of the interfollicular epidermis, similar to the distribution patterns of that in adult epidermis. Postembedding immunoelectron microscopy showed anti-citrulline peptide antibody immunogold labeling over the cytoplasmic intermediate filament network in the periderm and the intermediate cell layers. These results demonstrate an orderly formation of deiminated proteins in different layers of embryonic epidermis and suggest important roles for peptidylarginine deiminases in human epidermal morphogenesis.

Cells, Cultured↗
PubMed2003

Erythrokeratoderma variabilis without connexin 31 or connexin 30.3 gene mutation: immunohistological, ultrastructural and genetic studies.

Erythrokeratoderma variabilis, characterized by migrating erythema and fixed keratotic plaques, is a rare congenital disorder which has recently been connected with connexin (Cx)30.3 or Cx31 gene mutations. We present a 9-month-old Japanese girl who exhibited the typical clinical features of the disease, but carried no Cx30.3 or Cx31 gene mutations. Histopathologically, regular acanthosis with hyperkeratosis and hypergranulosis was observed in her lesional skin. Upregulation of involucrin and loricrin expression, and a weak expression of Cx26 was immunohistochemically observed in the upper spinous and granular layers. Electron microscopy revealed no abnormality in the keratin filaments, cornified cell envelope or gap junctions. Direct sequencing revealed no pathogenetic mutations in the Cx26, Cx30.3, Cx31 or Cx31.1 genes in this patient. The results indicate that erythrokeratoderma variabilis is pathologically heterogeneous, and that abnormalities in keratinization other than Cx30.3 and 31 gene mutations may underlie some forms of this disease.

Connexin 26↗
PubMed2003

[A case of treatment on traumatic pseudoaneurysm of internal carotid artery occurred epistaxis].

We reported a case of traumatic pseudoaneurysm of internal carotid artery accompanied by skull base fracture, for which Guglielmi detachable coil(GDC) embolization surgery was very effective for recovery. A 53-year-old man met a traffic accident and was admitted to our hospital with blindness and epistaxis accompanied with shock. Balloon occlusion test showed a positive sign of traumatic pseudoaneurysm of internal carotid artery, and under the diagnosis GDC embolization surgery was performed on six days after the onset. The patient has completely recovered and keeps his wellness untill now after six months from the surgery except for loss of left eye vision. We believe that the endovascular surgery using stents will become the prime modality for treatment of traumatic pseudoaneurysm in the future.

Aneurysm, False↗
PubMed2003

[Spontaneous extra-cranial vertebral artery dissection accompanied with multiple cerebral infarctions due to re-canalization].

In this paper we report a case of vertebral artery occlusion caused by spontaneous extra-cranial vertebral artery dissection accompanied with cerebellar and thalamic infarctions due to recanalization. Furthermore, after a nine-week time lapse we performed PTA/stenting. A 62-year-old man with vertigo, dysarthria and nuchal pain without injury was admitted to our hospital. Emergent cerebral angiography revealed an occlusion of the right vertebral artery and the right PICA. The patient's symptoms gradually improved owing to local-fibrinolysis with urokinase for the right PICA via the left vertebral artery. Follow-up angiography (2 weeks later) showed re-canalization and dissection of the right vertebral artery. Treatment for spontaneous extra-cranial vertebral artery dissection is chosen, depending on whether there is co-lateral circulation or not. We obtained a good result using PTA/Stenting in this case of spontaneous extra-cranial vertebral artery dissection within nine weeks after onset.

Cerebellum↗
PubMed2002

Changes in gap junction distribution and connexin expression pattern during human fetal skin development.

Gap junctions are intercellular channels composed of connexin subunits that mediate cell-cell communication. The functions of gap junctions are believed to be associated with cell proliferation and differentiation and to be important in maintaining tissue homeostasis. We therefore investigated the expression of connexins (Cx)26 and 43, the two major connexins in human epidermis, and examined the formation of gap junctions during human fetal epidermal development. By immunofluorescence, Cx26 expression was observed between 49 and 96 days' estimated gestational age (EGA) but was not present from 108 days' EGA onwards. Conversely, Cx43 expression was observed from 88 days' EGA onwards. Using electron microscopy, the typical structure of gap junctions was observed from 120 days' EGA. The number of gap junctions increased over time and they were more common in the upper layers, within the periderm and intermediate keratinocyte layers rather than the basal layer. Immunoelectron microscopy revealed Cx43 labeling on the gap junction structures after 105 days' EGA. Formation of gap junctions increased as skin developed, suggesting that gap junctions may play an important role in fetal skin development. Furthermore, the changing patterns of connexin expression suggest that Cx26 is important for early fetal epidermal development.

Connexin 26↗
PubMedDate not supplied

Identifying the characteristic secondary ions of lignin polymer using ToF-SIMS.

The chemical structure of lignin, a complex, irregular polymer of phenylpropane units that occurs in plant cell walls, was investigated using time-of-flight secondary ion mass spectrometry (ToF-SIMS). The positive ToF-SIMS spectra of lignin isolated from pine and beech wood showed prominent secondary ions possessing guaiacyl (at m/z 137 and 151) or syringyl (at m/z 167 and 181) rings, which are the basic building units of lignin polymer. This shows that ToF-SIMS is a useful tool for lignin structural analysis. The peaks at m/z 137 and 167 were assigned as the C6-C1 ion, and the peaks at m/z 151 and 181 may be double-component, the C6-C1 ion and the C6-C2 ion. We confirmed the characteristic guaiacyl ions using a synthetic lignin model compound, dehydrogenation polymer (DHP), which was formed by polymerizing of unlabeled and deuterium-labeled coniferyl alcohols. The formation mechanism of the main secondary ions was deduced by labeling specific positions of coniferyl alcohols with a stable isotope to study the relationship between chemical structure and secondary ion formation in ToF-SIMS.

Deuterium↗